Dimerisation of nitrile oxides: A quantum-chemical study

T. Pasinszki, Balázs Hajgató, Balázs Havasi, Nicholas P C Westwood

Research output: Contribution to journalArticle

17 Citations (Scopus)

Abstract

The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH3) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation. The kinetic energy barrier depends on the nature of the substituent X, generally increasing with decreasing electronegativity and increasing π-donor ability of the substituent: F (ΔG298 = 0 kJ mol-1) <Cl (72) <Br (90) <CH3 (104) <CN (114) (MR-AQCC(2,2)//UB3LYP/cc-pVTZ). Following initial C-C bond formation, three possible dinitrosoethylene diradical pathways are explored. Two of them are new, and one of them is a low-energy three-step path with implications for cycloreversion, tautomerism and detection of dinitrosoethylene intermediates. Alternative one-step, concerted [3 + 2] and [3 + 3] cyclodimerisation processes leading to 1,2,4-oxadiazole-4-oxides and 1,4,2,5-dioxadiazines have kinetic energy barriers around 100-240 kJ mol -1 (CCSD//B3LYP), some 1.6 to 2.5 times higher than those leading to furoxans, supporting the experimental observations of furoxan formation as nitrile oxide loss channels during storage, trapping/re-vaporisation and reactions of nitrile oxides. Potential polymerisation initiation processes for NCCNO, involving the 1,2-dipolar NC substituent are also explored.

Original languageEnglish
Pages (from-to)5263-5272
Number of pages10
JournalPhysical Chemistry Chemical Physics
Volume11
Issue number26
DOIs
Publication statusPublished - 2009

Fingerprint

Nitriles
Dimerization
nitriles
dimerization
Oxides
oxides
Energy barriers
Kinetic energy
Oxadiazoles
Electronegativity
kinetic energy
Vaporization
Polymerization
polymerization
trapping
furoxans
1,2,5-oxadiazole 2-oxide

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Physics and Astronomy(all)

Cite this

Dimerisation of nitrile oxides : A quantum-chemical study. / Pasinszki, T.; Hajgató, Balázs; Havasi, Balázs; Westwood, Nicholas P C.

In: Physical Chemistry Chemical Physics, Vol. 11, No. 26, 2009, p. 5263-5272.

Research output: Contribution to journalArticle

Pasinszki, T. ; Hajgató, Balázs ; Havasi, Balázs ; Westwood, Nicholas P C. / Dimerisation of nitrile oxides : A quantum-chemical study. In: Physical Chemistry Chemical Physics. 2009 ; Vol. 11, No. 26. pp. 5263-5272.
@article{6b86cd9d4d3f462e867f77b8a5dd52fa,
title = "Dimerisation of nitrile oxides: A quantum-chemical study",
abstract = "The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH3) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation. The kinetic energy barrier depends on the nature of the substituent X, generally increasing with decreasing electronegativity and increasing π-donor ability of the substituent: F (ΔG298 = 0 kJ mol-1) <Cl (72) <Br (90) <CH3 (104) <CN (114) (MR-AQCC(2,2)//UB3LYP/cc-pVTZ). Following initial C-C bond formation, three possible dinitrosoethylene diradical pathways are explored. Two of them are new, and one of them is a low-energy three-step path with implications for cycloreversion, tautomerism and detection of dinitrosoethylene intermediates. Alternative one-step, concerted [3 + 2] and [3 + 3] cyclodimerisation processes leading to 1,2,4-oxadiazole-4-oxides and 1,4,2,5-dioxadiazines have kinetic energy barriers around 100-240 kJ mol -1 (CCSD//B3LYP), some 1.6 to 2.5 times higher than those leading to furoxans, supporting the experimental observations of furoxan formation as nitrile oxide loss channels during storage, trapping/re-vaporisation and reactions of nitrile oxides. Potential polymerisation initiation processes for NCCNO, involving the 1,2-dipolar NC substituent are also explored.",
author = "T. Pasinszki and Bal{\'a}zs Hajgat{\'o} and Bal{\'a}zs Havasi and Westwood, {Nicholas P C}",
year = "2009",
doi = "10.1039/b823406j",
language = "English",
volume = "11",
pages = "5263--5272",
journal = "Physical Chemistry Chemical Physics",
issn = "1463-9076",
publisher = "Royal Society of Chemistry",
number = "26",

}

TY - JOUR

T1 - Dimerisation of nitrile oxides

T2 - A quantum-chemical study

AU - Pasinszki, T.

AU - Hajgató, Balázs

AU - Havasi, Balázs

AU - Westwood, Nicholas P C

PY - 2009

Y1 - 2009

N2 - The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH3) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation. The kinetic energy barrier depends on the nature of the substituent X, generally increasing with decreasing electronegativity and increasing π-donor ability of the substituent: F (ΔG298 = 0 kJ mol-1) <Cl (72) <Br (90) <CH3 (104) <CN (114) (MR-AQCC(2,2)//UB3LYP/cc-pVTZ). Following initial C-C bond formation, three possible dinitrosoethylene diradical pathways are explored. Two of them are new, and one of them is a low-energy three-step path with implications for cycloreversion, tautomerism and detection of dinitrosoethylene intermediates. Alternative one-step, concerted [3 + 2] and [3 + 3] cyclodimerisation processes leading to 1,2,4-oxadiazole-4-oxides and 1,4,2,5-dioxadiazines have kinetic energy barriers around 100-240 kJ mol -1 (CCSD//B3LYP), some 1.6 to 2.5 times higher than those leading to furoxans, supporting the experimental observations of furoxan formation as nitrile oxide loss channels during storage, trapping/re-vaporisation and reactions of nitrile oxides. Potential polymerisation initiation processes for NCCNO, involving the 1,2-dipolar NC substituent are also explored.

AB - The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH3) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The rate determining step for all but the F-species is the first, corresponding to the C-C bond formation. The kinetic energy barrier depends on the nature of the substituent X, generally increasing with decreasing electronegativity and increasing π-donor ability of the substituent: F (ΔG298 = 0 kJ mol-1) <Cl (72) <Br (90) <CH3 (104) <CN (114) (MR-AQCC(2,2)//UB3LYP/cc-pVTZ). Following initial C-C bond formation, three possible dinitrosoethylene diradical pathways are explored. Two of them are new, and one of them is a low-energy three-step path with implications for cycloreversion, tautomerism and detection of dinitrosoethylene intermediates. Alternative one-step, concerted [3 + 2] and [3 + 3] cyclodimerisation processes leading to 1,2,4-oxadiazole-4-oxides and 1,4,2,5-dioxadiazines have kinetic energy barriers around 100-240 kJ mol -1 (CCSD//B3LYP), some 1.6 to 2.5 times higher than those leading to furoxans, supporting the experimental observations of furoxan formation as nitrile oxide loss channels during storage, trapping/re-vaporisation and reactions of nitrile oxides. Potential polymerisation initiation processes for NCCNO, involving the 1,2-dipolar NC substituent are also explored.

UR - http://www.scopus.com/inward/record.url?scp=70349237300&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=70349237300&partnerID=8YFLogxK

U2 - 10.1039/b823406j

DO - 10.1039/b823406j

M3 - Article

C2 - 19551193

AN - SCOPUS:70349237300

VL - 11

SP - 5263

EP - 5272

JO - Physical Chemistry Chemical Physics

JF - Physical Chemistry Chemical Physics

SN - 1463-9076

IS - 26

ER -